The present invention relates to a vibration damper assembly for an engine having a crankshaft, which vibration damper assembly is disposed between the engine crankshaft and a torque transmitting device such as a friction type clutch or a hydraulic torque converter.
Japanese Patent Second (examined) Publication (Tokkosho) 57-18049 (JP-B2) discloses a vibration damper assembly for an internal combustion engine. This known vibration damper assembly comprises a torsional vibration damper including torsional springs, and a resilient drive plate which serves as a bending stress damper. Two mass bodies serve as an input member and an output member of the torsional vibration damper. The resilient drive plate has an inner peripheral portion connected to the crankshaft at a rear end thereof, and an outer peripheral portion connected to the input member of the torsional vibration damper. The output member of the torsional vibration damper is rotatably supported via a bearing on a main drive shaft.
According to this known damper assembly, as the resilient drive plate is disposed radially inward of the input member of the torsional vibration damper, it is difficult to increase a radial dimension of the resilient drive plate to a satisfactory level in relation to the thickness thereof. Further, as the output member of the torsional vibration damper is rotatably mounted on the main drive shaft near its axial end, the main drive shaft must have sufficient strength to support the same.
An object of the present invention is to provide a vibration damper assembly in which, without any increase in an outer diameter of the assembly, a radial dimension of a resilient drive plate may be incresed to a satisfactory level in relation to a thickness thereof, thus facillitating adjustment of the bending vibration characteristic of the resilient drive plate and enables a desired power transmission characteristic through the vibration damper assembly to be achieved.